Question

solve by multiplying (x-y)(x^2+2xy+y^2)

Answer 1

(x - y)(x^2 + 2xy + y^2) = (x - y)(x + y)^2.

Expanding:
= x(x^2 + 2xy + y^2) - y(x^2 + 2xy + y^2)
= x^3 + 2x^2y + xy^2 - x^2y - 2xy^2 - y^3
= x^3 + x^2y - xy^2 - y^3.